Photographic elements containing antihalation layers



Patented Dec. 12 1939 UNITED STATES .PATENT OFFICE" PHOTOGRAPHIC ELEMENTS CONTAINING ANTIHALATION LAYERS No Drawing. Application December 13, 1938, Serial No. 245,528

11 Claims.

This invention relates to antihalation layers for photographic elements. More particularly, it relates to photographic plates or films bearing an antihalation layer on the reverse side.

5 This invention has for an object the preparation of photographic bearing elements bearing a removable antihalation layer. A further object is the preparation of antihalation layers which are removable in the ,weak acid-containing l baths used in photographic processing methods. A further object is the preparation of such layers which do not adversely affect the photographic images contained in photographic elements during processing. A still further ob- 15 ject is the preparation of antihalation films containing antihalation layers which do not afiect the sensitivity of photographic emulsions in contact therewith. A still further object is to prepare an antihalation film which does not dete- 30 riorate or become tacky upon storage. Other objects include the provision of film-forming dye-carrying layers which do not contaminate alkaline developer baths nor deposit contaminations in developing baths which act as culturing gr, mediums for germicidal propagation with its resultant deterioration of the developer. Still other objects will appear hereinafter.

The above and other objects are accomplished by the use of polymeric amino-nitrogen-containg ing bodies which are insoluble in water and ammonium hydroxide solutions but soluble in 2% acetic acid as the film-forming binding agent for antihalation layers of photographic elements. The antihalation layers contain in addition to 5 the binding agents a light screening dye or pigment. The dye or pigment is generally absorptive of light of wave lengths at which the photographic emulsion is sensitive.

As suitable polymeric amino-nitrogen bodies are deacetylated chitin which is described in Rigby United States Patent 2,040,879; the acid soluble reaction products of proteins with carbonyl compounds such as lower aliphatic aldehydes and ketones and amines having less than 5 nine carbon atoms in which the amino-nitrogen is joined to the aliphatic carbon, for example, those disclosed in MeigsUnited States Tatent 2,143,023, January 10, 1939; the amino-celluloses soluble in dilute acetic acid and containing an 50 amino-nitrogen removed from the cellulose nucleus by a chain of atoms comprising at least one carbon atom, for example, those described in Hardy United States Patent 2,136,296; cellulose amines which are soluble in a stoichiometri- 55 cal amount or 5% aqueous acetic acid containing directly attached to the cellulosic nucleus from 0.5 to 1.5 amino-nitrogens per glucose unit, these amino-nitrogens being attached to nucleus carbon atoms, such compounds are disclosed in Has,- kins United States Patent 2,136,299; reaction 5 products of vinyl ketone polymers with amino compounds, such products are described in Balthis United States Patent 2,122,707; the products obtained by treating resins having ketone groups'with an excess of ammonia or the equivalent thereof and hydrogenating the resulting mixture catalytically at superatmospheric pressure and temperature, such as those'described in Greenewalt United States Patent 2,063,158; polymeric amino alcohol esters of acrylic and 16 substituted acrylic acids, for example, those described in Harmon United States Patent 2,138,- 762, November 29, 1938; and the polymeric alcohol methacrylates described in Graves copending application Serial No. 21,807, filed May 16, I935, 20 etc., singly or incombination. These polymeric amino-nitrogen containing substances are insoluble in water and 5% aqueous ammonia but, soluble in aqueous acetic acid of some concentration within the range 2-5%. These soluble in 2% 'acetic acid are preferred. These, polymeric-nitrogen containing substances may be divided in several groups as follows:

Those which may be termed cellulose derivatives. This includes deacetylated chitin and the alkylaminoand amino-alkylcelluloses aboveidentified.

(2) Synthetic resins having sufiicient aminonitrogen to produce the proper solubility. This group is distinct in that the highly polymeric 35.

molecules are built up wholly by artificial means. They are not synthesized by nature. In addition to the resinous polymeric amino alcohol esters of acrylic acid or of its homologs substituted in the alpha position by a hydrocarbon 40 radical, there may be-employed resinous reaction products of phenols, aldehydes and ammonia or primary or secondary amines, e. g., the reaction product of metacresol, formaldehyde and dimethylamine. (3) Protein derivatives containing sufiicient amino-nitrogen to enable them to meet the solubiiity requirements of the definition above given,

e. g., piperidylmethylzein, dimethylaminomethylzein, and dimethylaminoethyl zein.

The light screening materials include watertolerant and spirit soluble dyes, blue, green, yellow, magenta and red; either singly or in combinations to produce black, deep blue, green and red dyes. Halation of blue sensitive and orthochromatic emulsions can be minimized by the use of black and red non-halation layers. Panchromatic emulsions, theoretically, require black non-halation layers although green and deep blue 5 can be used advantageously. Natural-occurring pigments of the above-mentioned colors may be used by this invention since the entire nonhalation is removed during processing. Metallodye complexes and inorganic, colored compounds are likewise suitable if they are of appropriate colors and have no adverse efiect on the photographic emulsion which comes into contact with the non-halation layer when rolled up.

The polymeric amino-nitrogen containing 5 agents are dissolved in a dilute aqueous acid solution, the light screening material is incorporated in the solution, coated upon the support of the photographic element, and dried. The dye or pigment is of such tinctorlal strength or is added in suflicient amounts to stop the passage of light rays. The aqueous acid solution may be water alone or water in admixture with a water-miscible solvent such as methanol, ethanol, acetone, etc. The acid may be of inorganic or organic type, preferably the latter, but should be chosen so that it does not adversely affect the light sensitive emulsion.

The solution may be coated upon the back of the transparent plate or film support by any of the conventional methods, dipping, transfer or beading rollers, spraying, immersion beading, etc. In general a very thin layer upon the order of 0.5 to 20 a is sufficient for the purpose.

The invention will be further understood but is not intended to be limited by the following examples.

Example I A coating solution having the following position comwas prepared by adding the acid to the water and then the deacetylated chitin (soluble in 2.0% acetic acid) and then the dye with agitation. The dye was first dissolved in a little ethanol. The slightly viscous mixture obtained thereby was coated on to the back side of a transparent cellulose nitrate film base which carried upon its face a panchromatic emulsion, by means of a beading roller and allowed to dry.

The resulting film was smooth, uniform and free from repellent spots and coating streaks. It was found to have excellent antihalation characteristics and was free from tackiness. It was not affected by development of the film in the usual manner with metol-hydroquinone, nor did it alter the characteristics of the developer in any way,- The layer was removed in an acid fixing bath and upon subsequent soaking and washing.

Ezcample II A coating solution of the following composition was prepared in a manner similar to Example I upon a cellulose acetate film base which contained upon,its face a panchromatic emulsion. The film had the same properties and characteristics as that described in Example I.

The following examples illustrate other coating solutions which may be used. The light screening materials are added to the solutions before coating the photographic element.

Ethyl alcohol (35% water) 95.0

The antihalation layers of this invention are not dissolved by the alkaline developer or water rinse baths, but are solubilized by the acid present in and at the concentration usually employed in ordinary photographic processing, such as acid stop baths, acid' fixing baths, acid hardening fixing baths, acid bleach baths, reversal bleach baths and acid developers.

If it is desired to remove the antihalatlon layer before fixation, it may be solubilized by immersing the film in weak acid baths, e. g., acetic or citric acid baths, which are commonly employed as a stop bath between the development and fixation stages of processing.

In general, any dye which possesses the property of absorbing actinic light, of being readily dissolved or destroyed in ordinary photographic baths and of not injuring such baths may be used. The dye or dyes to be used in any specific instance are primarily determined by the light sensitivity of the emulsion. Such emulsions are usually gelatin silver halide emulsions which contain sensitizers such as cyanine, carbocyanine, pseudo-cyanine, cyazine bases and salts. That is, it must be absorptive of light of the wave lengths to which the emulsion is sensitive. In general the dye should be added in an amount suflicient to give a photographic density of 0.8 or the amount of dyed layer should be sufiicient to give such a density, As examples of additional useful dyes, mention is made of:

Auramine (C. I. 655) Helianthin (C. I. 142, 146) Brilliant yellow S (C. I. 144) Chrysoin (C. I. 148) Acid blue black (C. I; 246) Rhodamine (C. I. 749, 750, 751, 746, 753, 761, 763) Fuchsin (C. I. 677) Safranine G (C. I. 841) Ponceau SR (186) Crocein scarlet (C. I. 277,251, 286, 252, 291, 183) Azorubin (C, I. 1'79) Safranine O (C. I. 841) Ponceau 2R (C. I. 79)

Spirit solution nigrosine (C. I. 864) Metanil yellow (C. I. 138) In the event it is desired to have the non-halation layer remain on the film, then the dye concentration is reduced to about 1/10 to 1/20 that described above and protein hardeners, e. g., alum, etc. are added to the coating solutioncontaining the polymeric amino-nitrogen contaimng binding agent. Thus, where it is desirable to have a weakly colored blue to blue-green tint to the finished film, this may be accomplished by the last mentioned procedure resulting in a permanent antihalatlon layer. 7

This invention has the advantage that a nontacky antihalation layer which is insoluble in water or alkaline solutions, but is readily soluble in dilute acid baths may be quickly prepared. A further advantage is the fact that stable nontacky non-reactive antihalation layers may be easily prepared. Thus, films may be tightly rolled up with the antihalation layer in direct contact with the emulsion layer and stored for long periods of time without any detrimental effects.

As many apparently widely different embodiments of this invention may be. made without de: parting from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments hereof except as defined by the appended claims.

I claim:

1. A photographic element comprising a transparent support, a coating of sensitized material upon one side of the support and a layer upon the other side of'the support comprising a polymeric amino-nitrogen containing body which is insoluble in water and ammonium hydroxide solution, but soluble in dilute acetic acid, and an antihalation dye.

2. A photographic element comprising a transparent support, an emulsion of sensitized material upon one side of the support and a layer upon the other side of the support comprising a polymeric amino-nitrogen containing body which is insoluble in water and 5% ammonium hydroxide solution, but soluble in 2% acetic acid, and an antihalation dye.

3. A photographic element comprising a transparent support, an emulsion of sensitized material upon one side of the support and a layer upon the other side of the support comprising a polymeric amino-nitrogen containing body which is 1 insoluble in water and 5% ammonium hydroxide solution, but soluble in 2% acetic acid, and a maforth in claim 3 wherein the emulsion is an orthochromatic emulsion.

6. A photographic element comprising a transparent support, a gelatino silver halide emulsion upon one side of 'the support and a layer upon the other side of the support comprising a polymeric amino-nitrogen containing body which is insoluble in water and- 5% ammonium hydroxide solution, but soluble in 2 to 5% acetic acid, and an antihalation dye.

7. A photographic element comprising a transparent support, a gelatino silver halide emulsion upon one side of the support and a layer upon the other side of the support comprising deacetylated chitin and a material absorptive of the rays to which the emulsion is sensitized.

8. A photographic element comprising a transparent support, a gelatino silver halide emulsion upon one side of the support and a layer upon the other side of the support comprising a polymeric amino alcohol ester of acrylic and substituted acrylic acids, said polymeric acid ester being soluble in aqueous acetic acid of concentrations within the range 2 to 5%, but insoluble in water and 5% aqueous ammonia, and a material absorptive of the rays to which the emulsion is sensitized.

9. Aphotographic element as set forth in claim 8 wherein the ester is dicyclohexylaminoethyl methacrylate and a material absorptive of the rays to which the emulsion is sensitized.

l0. Aphotographic element comprising a transparent support, gelatino silver halide emulsion upon one side of the support and a layer upon the other side of the support comprising a protein derivative containing suflicient amino-nitrogen to render it soluble in 2 to 5% acetic acid, but insoluble in water and 5% aqueous ammonia comprising an amino-zein and a material absorptive of the rays to which the emulsion is sensitized.

11. A photographic element as set forth in claim 10 wherein the protein derivative is piperidylmethyl zein.

GEORGE A. DAWSON. 

